Compositions that produce lather for shaving have been known for many decades. One type of known shaving composition that has been used for years is whisked with a brush to incorporate air and thereby generate lather.
Another type of known lather producing shaving composition is aerosol shaving compositions containing volatile organic liquids under super atmospheric pressure. Such compositions are disclosed in U.S. Pat. No. 2,655,489 to Spitzer et al. In these lather producing compositions, the vapor pressure of the volatile liquids is substantial, say 25 to 40 P.S.I.G. so that the compositions are immediately converted to lather when released from the aerosol container to the atmosphere.
A more recent type of lather producing shaving composition is the gel lather producing composition disclosed in U.S. Pat. No. 3,541,581 to Monson. In the compositions of this patent there are employed organic liquids with vapor pressures of 6 to 14 P.S.I.G. According to the Monson patent, the compositions when released from their container would quickly expand to a lather if not for the inclusion of a gelling agent which restrains lather formation until the shaving composition is applied to the skin in the form of a gel.
More particularly, the Monson compositions are post foaming shaving gel compositions that are dispensed as gels, but produce a lather when rubbed on the face. The compositions comprised a soap solution, a gelling agent, and an organic liquid having a vapor pressure from about 6 to 14 P.S.I.G. at a temperature from about 90 to 100F. The organic liquid is the post foaming agent.
In order to dispense Monson's compositions with their super-atmospheric vapor pressures in the form of gels, it is necessary to employ an especially complex and expensive aerosol container, that in addition to the usual components also includes a bag or piston or equivalent device, as shown in FIG. 4 of the Monson patent.
While Monson states that his post-foaming gels can be packaged in collapsible metal tubes, this is not practical. Because of the super-atmospheric pressure of the compositions, it is necessary to use an aerosol valve and dispensing spout. If a tube cap were used, the composition would continue to gush from the container until the cap was screwed into place. Further, the crimped end of the collapsible tube would unravel and pop open under sustained pressure of the composition. In addition, the pressure would maintain the collapsible metal tube in a constantly expanded state, regardless of the amount of material in the tube. As a consequence, as the contents were emptied, the gel would tend to expand to fill the tube, and then be expelled as an aerated gel or lather.
The Monson compositions because of their above atmospheric vapor pressure cannot be exposed to elevated temperature in storage, shipping and use without causing problems of premature expansion.
This invention relates to shaving compositions which are improvements over those of our U.S. Pat. No. 4,744,979. The latter patent provided shaving compositions with sub-atmospheric vapor pressures that generate a lather when rubbed on the face, and that can be packaged in inexpensive containers, such as collapsible tubes, without premature expansion of the tube during storage, shipment and use.
In the examples of that patent, n-pentane was employed as the lather-generating agent. Superfatting agents and small amounts of somewhat higher boiling hydrocarbons, such as hexane, were employed to raise the boiling point or the organic phase. N-pentane boils at 36.degree. C., and with these additives the boiling point could be raised to about 40.degree. C. The use of larger amounts of these vapor pressure depressants adversely affected lather formation and lather stability.
There is need to raise the boiling point of the compositions to at least about 50.degree. C. Temperatures approaching this can be encountered during shipping and storage. In addition, substantial pressure can develop in the container as the boiling point is approached. Such pressures can cause the seals on conventional collapsible tubes to burst, if such pressures are maintained for an extended period of time.
TABLE 1 __________________________________________________________________________ Increase Over Fatty Acids Mineral Boiling Expected Boiling Composition plus Surfactants, % Fatty Acids, % Free Fatty Acids, % Oil % Point .degree.C. Point .degree.C. __________________________________________________________________________ A 11.5 7.7 4.2 3.0 41 1 B 12.8 12.8 4.9 2.9 45 3 C 13.1 9.3 4.2 2.9 45 4 D 13.5 9.7 1.7 2.9 46 5 E 14.6 10.8 3.8 2.9 48 7 F 15.6 11.8 4.2 2.9 46 5 G 16.1 12.3 2.5 5.5 50 10 H 16.2 14.6 4.6 7.6 55 10 I 15.4 15.4 5.0 4.5 56 11 J 16.3 14.6 4.5 5.3 57 12 K 16.4 14.7 4.4 6.6 56 12 L 15.8 15.8 5.0 4.5 57 12 M 16.8 14.9 5.1 4.5 59 15 __________________________________________________________________________ All percentages are by weight based on the total weight of composition All compositions contain approximately 4.5% isopentane Soap is triethanolamine palmitatecocoate Surfactant is lauroyl diethanolamide Mineral oil has a viscosity of 4 cs at 38 C.
TABLE 2 __________________________________________________________________________ Increase over Fatty Acids Free Fatty Boiling Expected Boiling Composition Plus Surfactants, % Fatty Acids, % Acids, % Oil % Point .degree.C. Point .degree.C. __________________________________________________________________________ N 14.8 11.0 4.0 (1) 6.7 49 5 O 14.8 11.0 4.0 (2) 6.7 47 6 P 14.8 11.0 4.0 (3) 6.7 49 7 Q 14.8 11.0 4.0 (4) 6.7 49 9 R 14.8 11.0 4.0 (5) 6.7 45 6 S 14.6 12.8 6.1 (1) 6.7 56 9 T 14.6 12.9 6.1 (2) 6.7 53 9 U 14.6 12.7 6.1 (3) 6.7 54 10 V 15.4 15.4 5.0 (1) 4.5 50 8 W 15.4 15.4 5.0 (2) 4.5 48 9 X 15.4 15.4 5.0 (3) 4.5 49 8 I 15.4 15.4 5.0 (6) 4.5 56 11 __________________________________________________________________________ All percentages are by weight based on the total weight of composition All compositions contain approximately 4.5% isopentane N,O,P,Q,R,V,W,X,Y Soap is triethanolamine palmitatecocoate S,T,V Soap is diethanolamine palmitatecocoate N,O,P,Q,R,S,T,U Surfactant is lauroyl diethanolamide (1) isopropyl myristate (2) Corn oil (3) dimethyl polysiloxane, 10 cs at 25 C. (4) isocetyl alcohol (5) lauryl lactate (6) mineral oil, 4 cs at 38 C.
TABLE 3 __________________________________________________________________________ Increase over Fatty Acids Free Fatty Oil Boiling Expected Boiling Composition plus Surfactants, % Fatty Acids, % Acids, % (Type) % Point, .degree.C. Point .degree.C. __________________________________________________________________________ Y 14.8 11.0 4.0 (--), 0 39 3 Z 15.7 11.9 4.2 (1), 0.9 40 2 AA 15.6 11.8 4.2 (1), 1.9 46 7 BB 15.6 11.8 4.2 (1), 2.9 48 7 CC 15.6 11.8 4.2 (2), 3.0 47 6 DD 15.6 11.8 4.2 (3), 3.0 46 5 EE 15.6 11.8 4.2 (1), 1.1 50 5 __________________________________________________________________________ All percentages are by weight based on the total weight of composition EE contains approximately 4.5% npentane, all other compositions contain approximately 4.5% isopentane All compositions: surfactant is lauroyl diethanolamide and soap is triethanolamine palmitatecocoate (1) mineral oil, 4 cs at 38 C. (2) mineral oil, 7 cs at 38 C. (3) mineral oil, 21 cs at 38 C.
It is an object of the instant invention to provide a shaving preparation that, when rubbed on the beard develops a shaving cream lather within a few seconds, i.e., within about ten seconds. Another object is that the shaving cream lather should be both voluminous and stable. An additional object is that the composition that is used to form the shaving cream lather should not boil below about 50.degree. C.